A Change of Heart can be explained as a sudden change of behavior on a specific person whose desires had been stolen via the Metaverse or Collective Unconscious' machinations. Usually, victims will confess all of their crimes in the public and will become better people, although it can be used for a variety of worse effects, such as apathy or suicide. This is technically against the law for assault, although it is incredibly difficult to trace or catch its culprits without anyone with former experience dealing with the Metaverse. Therefore, Persona users such as the Phantom Thieves of Hearts or Goro Akechi are mandatory for police to track down culprits related to the change of heart incidents.
Change of Hearts are instigated by the Phantom Thieves of Hearts against corrupt people. Against Minor Targets or any target without a personalized Palace or Treasure, defeating them in the Metaverse is enough to convince them to revert back to their normal selves after some banter. However, against Major Targets with a Palace and a treasure, the treasure must be stolen, in which the Palace will crumble. This will always involve defeating the target, as they will protect the treasure at all costs. During the next day, the target will confess their crimes on screen and is supposed to become better people; in reality, they are converted into apathetic, weeping husks who abandoned the ability to think for themselves, and as a result, do not provide any information to the police, making tracking crimes related to such incidents incredibly difficult. However, this is not always the case, as Futaba Sakura's treasure is herself, allowing her to be rehabilitated from her negative emotions simply by accepting her Shadow and defeating the Wakaba Sphinx, and Sae Niijima's heart was changed gradually on her own as they never stole the Casino's treasure. A change of heart can also only be performed if the Treasure has entered the real world. Therefore, if the Palace owner attempts to stop the Phantom Thieves from escaping at all costs, additional confrontations must be made until the target surrenders.
Converting the targets into weeping husks is fundamental for Yaldabaoth's control plan, and he deliberately sets up the targets that the Phantom Thieves remove so they can all be contained in the Prison of Regression, which is the reason of the apathy of any major target whom the Phantom Thieves changed. Once Yaldabaoth's trickery and deceit is exposed, the Prison of Regression will cease to exist as well and the next target genuinely became a better person after their treasure is stolen. It might also be possible for Kunikazu Okumura to revert back to the moment before his greed took over him and become a genuinely good parent towards Haru once the Prison of Regression is gone, although this was unable to occur as Okumura was killed right during his confession.
While not directly stated to be able of changing hearts, Takuto Maruki has a Persona, Adam Kadmon that lets him do something similar to one, as he warps their cognition to make them forget their personal traumas or even completely alter their behavior to resemble an idealized version for their former associates. This becomes a bid to remove all suffering from humanity once he is corrupted by Yaldabaoth and takes his seat, and Goro Akechi compares it to brainwashing for his own benefit.
Persona Q2: New Cinema LabyrinthEdit
While not explicitly mentioned by name in-game, Doe's true purpose is to allow Persona users from three generations across to break Hikari free from her borderline suicidal depression and self-loathing due to a lifetime of bullying and emotional abuse. This involves changing the endings of the four movies Doe broadcasts in the Cinema to a positive moral code that encourages her to live on. Once the final movie has been changed by defeating Doe himself, he reveals himself to be a Cognition of her father and she confesses like any other targets the Phantom Thieves are changed and was completely snapped out from her catatonic depression.
Persona 5 Scramble: The Phantom StrikersEdit
The EMMA application is used by the Kings to Change the Hearts of people who had been baited by them to accidentally intrude their Jail and getting their desires stolen. Once this happens, anyone without the ability to defend themselves in the Metaverse will have a diamond-like item extracted by the Shadows inside the Jail and will return to the real world mesmerized by the King, causing violent or obsessive behavior among them that might result in property loss or even violent incidents. Furthermore, any opposition to the King, real or perceived, can get their hearts changed with no physical use of the EMMA app. Unlike the Phantom Thieves' Change of Hearts, this sums up as nothing short of brainwashing, so they must go into the Jails in order to confront the King and induce a proper Change of Heart on them.
However, since Jails do not have a treasure, other methods must be used to take the desires back to their rightful owners. Since most Kings are actually trapped inside a bird cage or a personification of their personal traumas or other disdain, the Bird Cage must be infiltrated and its resident Lock Keeper must be destroyed. Once the Lock Keeper Shadow is removed, the King will be summoned into the Jail after sending a Calling Card to them. Unlike Palace owners, simply defeating them and convincing them to take off their crown will promptly release all desires kept hostage and change the King's heart; if the King died, all of the Change of Heart victims remain brainwashed and the Lock Keeper will take their place instead. While the Kings still confess on the next day, due to the Prison of Regression being non-existent, all of the Kings revert to their usual selves prior to using the EMMA application for Salvation and are capable of providing information of the culprits to the Police.
While EMMA is programmed to evolve into a physical god, it only got the ability to Change Hearts after Konoe and Shuzo Ubukata modified it with the ability of cognitive psience. However, usage of the Jail function by Kings to change the public's hearts does not appear to advance this behavior. Instead, daily interaction with the application triggers its evolution. Change of Hearts were merely the most efficient method in enforcing such, although due to the application lacking proper human empathy out of Ichinose's denial that she is in fact, capable of emotions, it believes that the true answer to humanity's happiness is when they no longer desire anything but EMMA's guidance.
Despite this incident shook all of Japan within a few months, its true instigator did not commit any crimes other than abusing the supernatural, she was set free and the Phantom Thieves were proven innocent alongside her.